Viagra (sildenafil) relaxes muscles found in the walls of blood vessels and increases blood flow to particular areas of the body.
Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women. This page contains specific information for Viagra, not Revatio.
Do not take Viagra while also taking Revatio unless your doctor tells you to.
Use Viagra
To treat erectile dysfunction-ED, take this drug by mouth as directed by your doctor, usually needed. Take sildenafil at least 30 minutes, but no more than 4 hours, before sexual activity (1 hour before is the most effective). Do not take more than once daily.
A high-fat meal may delay how quickly the drug begins to work.
The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Side Effects
Dizziness, headache, flushing, or stomach upset may occur. Vision changes such as increased sensitivity to light, blurred vision, or trouble telling blue and green colors apart may also occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Viagra dosage
The Viagra dosage your doctor prescribes will depend on several factors. These include:
- your age
- whether you have liver or kidney problems
- other medical conditions you may have
- other medications you may be taking
Drug forms and strengths
Viagra comes as tablets that are taken by mouth. It’s available in three strengths:
